Air conditioning mechanism



GQD. KINGSLAND AIR CONDITIONING MECHANISM April 18, 1939.

Filed Sept, 16, 1935 ain, yaw

4 GeoryeDKirgshnd Ill 55" Patented Apr. 18, 1939 AIR CONDITIONING MECHANISM George I). Kingsland, Minneapolis, Minn, as-

slg'nor to Minneapolis-Honeywell Regulator Company, Minneapolis, Minn a corporation of Delaware Application September 16, 1935, Serial No. 40,799

2 Claims. (01. 236-38) This invention relates to air conditioning mechanism in general and more particularly to unit ventilators.

An object of this invention is to provide a control system for unit ventilators or plenary wherein the damper is controlled in accordance with the temperature of a mixture of fresh air and recirculated air and wherein the heating element or radiator is controlled in response to space or room temperature.

In many localities in this country heating and ventilating codes stipulate that a predetermined amount of fresh air must at all times be admitted by the air conditioning mechanism or unit ventilator to the space or room to be heated. The amount of fresh air so admitted varies according to diil'erent requirements in the various localities.

It is therefore another object of this invention to provide an adjusting means for a control system of a unit ventilator or plenary system whereby a predetermined amount of fresh air may at all times be admitted in accordance with the heating and ventilating regulations of the various localities and whereby this predetermined amount of air may be easily adjusted.

A further object is to provide a control system of the class described wherein a predetermined amount of fresh air may be provided when the system is in operation, but wherein no fresh air is provided when the system is rendered inoperative.

Other objects of this invention will become apparent to those skilled in the art upon reference to the accompanying specification, claims and drawing, in which drawing:

Figure 1 is an elevational sectional view of a unit ventilator disclosing my control system applied thereto.

F'igure 2 is a sectional view of Figure 1.

Figure 3 is a perspective view with parts broken away showing the adjusting mechanism utilized in my invention.

Figure 4 is a schematicwiring diagram of the control system of my invention,

Although my invention may be applied to plenary systems it is shown in Figures 1 and 2 as being applied to a unit ventilator generally designated at iii. The unit ventilator I0 is shown to comprise a lower wall ii, an upper wall 12, a front wall l3 and rear walls I4 and I5. Side walls are also provided at I6 and I1 and the rear walls are connected together by a horizontally extending partition I8. The upper wall 12 is provided with a discharge opening l9, the front wall I3 is provided with a return air opening 28 and the which the various control elements may be located.

Located in the upper portion of the unit ventilator I I and above the horizontally extending partition I. is a radiator or heat exchanger 26 receiving a supply of heating fluid such as steam from a pipe 21. The supply of steam to the radiator 26 is controlled by means of a valve herein shown as a thermostatic valve 28 of usual design. The valve 28 may be manually operated or adjusted by the handle 28 or automatically operated in response to temperature by means of a remotely located control bulb 38 connected thereto by a capillary tube 3|, In the present invention the bulb 38 is located in the return air opening 26 so that the valve 28 is operated in response to return air temperature and consequently space temperature. Upon an increase in space temperature the valve 28 is moved towards a closed position and upon a decrease in space temperature the valve 28 is moved towards an open position. Conceivably, the valve 28 could be motor operated under the command ofa thermostat located either in the room or in the return air opening and such a mode of operation is within the contemplation of this invention,

Also located in the unit ventilator Hi just below the horizontal partition l8 are fans 33 and 34 for forcing air from the lower portion of theunit ventilator through openings 35 and 36 in the partition i8 over the radiator or heat exchanger 26 and discharging the same through the opening i9 into the space or room to be heated. The fans 33 and 34 are operated by an electric motor 31 through any suitable connecting means such as a shaft 38.

The amount of fresh air or return air delivered to the fans 33 and 34 is determined by means of a damper 48 mounted on brackets 4| suitably supported by shafts 42. Mounted on one of the shafts 42 is a crank 43 which is pivotally connected by means of a pin 44 to one end of a link 45; The other end of the link 45 contains an elongated slot 46 receiving a pin 41 mounted on a crank 48. The crank 48 is suitably operated by means of a proportioning motor 49 which may be of the form shown and described in Patent No.

2,032,658 issued to Willis H. Gille on March 3, 1936.

The damper 48 is biased toward a fresh air restricting or closed position by means of a tension spring 58, Upon operation of the proportioning motor 48 the damper 48 is moved away from the fresh air restricting or closed position against the action of the spring 58. Therefore, the damper 48 may be positioned, in a manner to be pointed out more fully hereafter, to determine whether fresh air or return air is to be admitted to the radiator 28 or the amount of fresh air or return air to be admitted.

located in the unit ventilator I8 is a temperature controller 5| of the potentiometer type and may take the form of the controller shown and described in Patent No. 2,041,050 issued to Lewis L. Cunningham on May 19, 1936. This temperature controller 5| is made responsive to the temperature of the mixture of fresh air and return air by placing a temperature control bulb 52 in the outlet opening of one of the. fans 88 and 84. the control bulb 52 being connected to the temperature controller 5| by means of a capillary tube 58.

Also located in the unit ventilator I8 is a variable resistance 54 the structure of which is shown in Figure 3. The temperature controller 5| and the variable resistance 54 are suitably connected to the proportioning motor 48 by means of conduits 55. The proportioning motor 48 receives its power from some source not shown through a conduit 58. 7 L

Referring now to Figure 3, the variable resistance 88 is shown to comprise three coils 51, 58 and 58 suitably mounted in a casing 88. Sliders 8|, 62 and 88 mounted on a shaft 84 and rotated by a knob are adapted to slide across the resistances 51, 58 and 58, respectively.

Referring now to Figure 4, the crank 48 is shown to be operated by bevelled gears 68 and 81 which in turn are operated by a shaft 88. Mounted on the shaft 88 is a gear 58 which is driven through a reduction gear train 18 by a motor rotor II. The motor rotor II is controlled by field windings 12, 18 and 14. Upon energization of the field winding 12 the motor rotor 1| and, consequently, the shaft 58 are maintained in predetermined positions against the tension of the spring 58 since the field winding 12 is not sufllciently strong to rotate the shaft 88 against the action of the tension spring 58, but is sumciently strong to maintain the shaft 88 in a given position. Upon energization of the field winding 14 along with energization of the field winding 12 the shaft 88 is rotated against the tension of the spring 58. The field winding 14 is not sufliciently strong in itself to operate the shaft 88 against the tension of spring 58. Upon energization of the field winding 18, which field winding 13 acts in opposition to field winding 12, the action of the field winding 12 is neutralized and the spring 58 is allowed to move the shaft 88 in the opposite direction.

Also mounted on the shaft 88 is a bevelled gear controller 8| is shown to comprise a slider 88 adapted to slide across a potentiometer coil 81 so that upon an increase in temperature the slider 88 is moved to the right and upon a decrease in temperature it is moved to the left as shown by the characters H and C.

The proportioning motor 48 also includes a relay mechanism comprising an armature 88 pivoted at 88. The armature 88 carries a contact arm 88 which is insulated from the armature 88 by means of an insulating member 8|. The armature 88 is moved about its pivot 88 by means of coils 82, 88, 84 and 85. The contact arm is adapted to engage spaced contacts 88 and 81 so that whenthe coil 82 is energized more than the coil 88 the contact arm 88 is moved into engage ment with the contact 81 and when the coil 88 is energized more than the coil 82 the contact arm 88 is moved into engagement with the contact 88.

Line wires leading from some source of powernot shown are designated at|88 and IN. The line wire I88 is connected to a switch I88. The switch I88 is in turn connected by wires I84 and I85 to the fan motor 81 and the fan motor 81 is in turn connected by a wire I88 to the other line wire I8I. Therefore, when the switch I88 is closed the fan motor 81 is placed in operation.

The switch I88 is also connected by wires I84 and I81 to one end of a primary II8 of a stepdown transformer III having a secondary H2. The other end of the primary H8 is connected by a wire I88 and a switch I82 to the other line wire I8I. Therefore, when the switches I82 and I88 are closed the step-down transformer III is energized.

One end of the secondary H2 is connected by wires H3, H4 and II! to the slider 8| of the variable resistance 88. The resistance 51 cooper- 'at'ing with the slider 8| is connected by a wire II8 to the left end of the potentiometer coil 81. The other end of the secondary H2 is connected by wires H1 and H8 to the resistance 58 of the variable resistance 88. The slider 88 cooperating with the resistance 58 is connected by a wire II8 to the right end of the potentiometer coil 81. The junction of the wire 8 and the resistance 58 is connected by a wire I28, a resistance I2I, a wire I 22 and a protective resistance I22 to the left end of the balancing potentiometer coil 18. The right end of the balancing potentiometer coil 18 is connected by a protective resistance I28 and wire I28 to the junction of wires H4 and H5. The lower end of the coil 82 is connected by a wire I24 to the junction of wires H8 and H4 and likewise the lower end of the coil 88 is -connected by a wire I25 to the Junction of wires H1 and I I8. The upper ends of the coils 82 and 88 are connected together by wires I28 and I21 and by wires I28 and I28 to the resistance 88 of the variable resistance 88. The slider 82 cooperating with the resistance 58 is connected by a wire I88 to the slider 88. The slider 18 cooperating with the balancing potentiometer coil 18 is connected by a wire I8I to the junction of wires I28 and I28.

From the above it is seen that the left hand end of the secondary II2, the lower end of the coil 82, the left hand end of the potentiometer coil 81 and the right hand end of the balancing potentiometer coil 18 are connected together. Likewise, the right hand end of the secondary II 2, the lower end of the coil 88, the right hand end of the potentiometer coil 81 and the left hand end of the balancing potentiometer coil 18 are connected together. It is also seen that the sliders 18 and 86 and the upper ends of the coils 92 and 93 are connected together. It, therefore, can be stated that the secondary I I2, the coils 92 and 93, and the potentiometers 81 and 19 are connected in parallel.

The contact 96 is connected by a wire I39 to one end of the coil 95, the other end thereof being connected by a wire I33 to one end of the field winding 13. The other end of the field winding 13 is connected by wires I34 and I35 to the contact 82. The contact 84 is connected by a wire I38, a resistance I31 and a wire I38 to the junction of wires H1 and I I8. The contact 91 is connected by a wire I32 to one end of the coil 94, the other end of which is connected by a wire I48 to one end of the field winding 14. The other end of the field winding 14 is connected by a wire I4I to the contact 85. The contact 83 is connected by a wire I42 to the wire I38. The left end of the secondary H2 is connected by wires I43 and I44 to the contact arm 98 and by wires I43 and. I45, to one end of the field winding 7 12, the other end of the field winding 12 being connected to the junction of wires I34 and I35.

With the parts in the position shown in the drawing, the temperature of the mixture of fresh and return air is normal and the slider 86 is in its mid position with respect to the potentiometer coil 81. By reason of this position of the slider 86 the damper 48 is likewise in a mid position and equal amounts of fresh air and return air are being delivered to the radiator 26. Referring specifically to Figure 4, it is seen that a circuit is completed from the secondary II2 through wires I43 and I45, field winding 12, wire I35, contacts 82 and 84, wire I36, resistance I31 and wires I38 and H1 back to the secondary II2. Completion of this circuit causes energization of the field winding 12 to maintain the shaft 68 and, consequently, the damper 48 in its adjusted position against the action of the tension spring 58.

Upon a decrease in temperature of the mixture of fresh and return air the slider 86 is moved towards the left with respect to the potentiometer coil 81. By reason of the parallel relationship pointed out above, such movement of the slider 86 causes partial short-circuiting or shunting of the coil 92 to decrease the energization thereof and to increase the energization of coil 93. This unequal energization of coils 92 and 93 causes movement of the contact arm 98 into engagement with the contact 96 to complete a circuit from the secondary II2 through wires I43 and I44, contacLarm 98 contact 96, wire I39, coil 95, wire I33, field winding 13, wires I34 and I35, contacts 82 and 84, wire I36, resistance I31 and wires I38 and H1, back to the secondary II2.

Completion of this circuit causes energization of the field winding 13 to neutralize the action of the field winding 12 to allow the spring 58 to move the damper 48 towards a fresh air restricting or closed position to increase the mixed air temperature, Movement of the motor 49 and the damper 48 towards a closed position causes left hand movement of the slider 18 with respect to the balancing potentiometer coil 19. This causes decreasing ofthe energization of coil 93 and in creasing of the energization of coil 92. The coils 92 and 93 become equally energized when the damper 48 has been moved sufilciently far towards a fresh air restricting position. When the coils 92 and 93 are rebalanced in this manner the contact arm 98 is moved out of engagement with contact 96 to the mid position shown in the drawing to de-energize the field winding 13 to allow the field winding 12 to maintain the damper 48 in its newly adjusted position against the action of the tension spring 58.

If the temperature of the mixture of fresh and return air should become sufficiently low so as to move the slider 86 to the extreme left hand position the damper 48 will be moved to an extreme fresh air restricting or closed position. Movement of the damper 48 to its extreme closed position is insured by the resistance I2I connected in series with the left hand end of the balancing potentiometer coil 19 whereby the proportioning motor 49 is moved sufiiciently far to cause breaking of the limit contacts 82 and 84 and to cause movement ofthe pin 41 downwardly in the slot 46. This breaks the circuit through field winding 12 to prevent overtravel of the proportioning motor. 6

Upon a rise in temperature of the mixture of fresh and return air so as to move the slider 86 out of its extreme left hand position the coil 93 is partially shunted or short-circuited to decrease the energization thereof and to increase the energization of the coil 92. This causes movement of the contact arm 98 into engagement with the contact 91 to complete a circuit from the secondary II2 through wires I43 and I44, contact arm 98, contact 91, wire I32, coil 94, wire I48, field winding 14, wire I4I, contacts 85 and 83, and wires I42, I38 and H1, back to the secondary II2. Completion of this circuit causes energization of field winding 14 which is sufiicient to move the pin 41 upwardly in the slot 46. When the pin 41 has proceeded to the upper extremity of the slot 46 the finger 88 permits the contact 82 to engage the contact 84 to cause energization of the field winding 12 in the manner pointed out above. Since the field windings 12 and 14 are both energized, counter-clockwise movement of the crank 48 and consequent movement of the damper 48 from the fresh air restricting position against the action of the tension spring 58 is brought about. Movement of the damper 48 towards an open position causes right hand movement of the slider 18 and when the damper 48 has been moved suiiiciently far the slider 18 rebalances the coils 92 and 93 to move the contact arm 98 out of engagement with the contact 91 to the mid position shown in Figure 4. This causes de-energization of the field winding 14 and the damper 48 is maintainedin its newly adjusted position by the energization of the field winding 12. If the damper 48 should be moved to an extreme open or return air restricting position, the finger 8| breaks contact between the limit contacts 83 and 85 to break the circuit through the field winding 14. In this manner overtravelling of the proportioning motor is prevented.

It is noted at this point that the circuits through the field windings 13 and 14 are completed through the coils 94 and 95 to increase the contact pressure of the contact arm 98 to prevent relay chatter. It is also noted that the circuits through field windings 12 and 13 are completedthrough the resistance I31 to add resistance to these circuits to compensate for the drop in resistance caused by the simultaneous energization of the oppositely acting windings 12 and 13.

In case of powenfailure or in case of opening'of the switches I82 or I83 the step-down transformer III is de-energized and, consequently, the control system outlined above is rendered inoperative. The spring 50 thereupon moves the damper 40 to an extreme closed or fresh air preventing position. The switch l02 is provided to prevent opening of the damper when it is desired to operate the fan alone for morning pick-up purposes.

In order to limit the closing movement of the damper 40 to comply with heating and ventilating regulations, I have provided the variable resistance 60 in the control circuit. Movement of the sliders ii, 62 and 63 downwardly in Figure 4 with respect to the associated resistances 51, 58 and 59 increases the resistance in the left hand end of the potentiometer coil 81 and decreases the resistance in the right hand end thereof. This downward movement of these sliders has the same effect as the right hand movement of the slider 86 with respect to its potentiometer coil 81. Therefore, with the slider 88 in the extreme left hand position the damper 40 is caused to be positioned in a partially open position. The farther the sliders BI, 62 and 63 are moved downwardly the farther openthe damper 40 will be positioned. Therefore, provision is made whereby the closing movement of the damper 40 may be limited and means are provided for adjusting this minimum position to meet the various heating and ventilating regulations that exist throughout the country. However, in case of power failure or in case of opening of the switch I03 to shut down the control system, the damper 40 is moved to its extreme closed position regardless of the setting of the variable resistance 60. Movement of the sliders Cl, 62 and B3 upwardly from the position shown has the opposite effect and limits movement of the damper 40 toward an open or return air restricting position. Such operation may be desirable in some instances and forms a part of this invention.

The above control system maintains the mixture of the fresh and return air at a constant temperature, this temperature preferably being about 65. In order to heat the air above 65 and to maintain a constant temperature in the space or room to be heated, the valve 28 is controlled in response to room or space temperature. Preferably, the thermostatic valve is so adjusted that it will be fully opened at or below and fully closed at or above 72 so that a large amount of heat will be delivered to the space when the temperature is below 70 and the amount of heat supplied will be decreased as the room temperature approaches 72 at which time .the supply of heat to the space will be discontinued.

From the above it is seen that I have provided a control system for a unit ventilator or plenary system wherein the temperature of the air being delivered to the radiator is maintained constant by the proper positioning of a damper and wherein the temperature in the space to be heated is maintained constant by controlling the radiation in the unit ventilator in response to space temperature. Provision is also made in the control system for limiting the closing movementof the damper whereby a minimum amount of air will at all times be admitted to the space to be heated but preventing the admission of fresh air when the unit ventilator is placed out of operation. By reason of my control system the amount of fresh air may be adjusted to comply with the various heating and ventilating codes that exist throughout the country.

Although I have disclosed one form of my invention for purposes of illustration, other forms thereof may become apparent to those skilled in the art and, therefore, this invention is to be limited only by the scope of the appended claims and the prior art.

lating the supply of fresh and return air circulated, means for biasing the damper means to fresh air preventing position, electric motor means acting against said biasing means for positioning said damper means, means for supplying power to the electric motor means from the electric circuit of the fan means, a three wire control circuit for said electric motor means, said three wire control circuit including a common wire, a first control wire which is adapted in cooperation with said common wire to cause said electric motor means to operate in one direction, and a second control wire which is adapted in cooperation with said common wire to cause said motor means to operate in the opposite direction, condition responsive electric current controlling means for controlling said motor means, said current .controlling means including a movable member connected to said common wire and means contacted by said movable member and adapted to place said common and control wires in cooperation respectively, a minimum position electric current controlling means interposed in one of said control wires between said condition responsive electric current controlling means, and said motor .m::.ns for preventing said condition responsive electric current controlling means from causing said motor means to move said damper means to a position stopping the supply of fresh air, and means for opening the electric circuit of the fan means for stopping the fan means and for interrupting the supply of power to the electric motor means whereby the biasing means moves the damper means. regardless of the condition responsive electric current controlling means and the minimum position electriccurrent controlling means, to a position for substantially stopping the supply of fresh air.

2. In an air conditioning system, the combination of, a conditioning chamber having air conditioning apparatus therein, electrically operated fan means for circulating fresh and return air through the conditioning chamber to a space to be conditioned, an electric circuit for supplying power to the fan means, damper means for regulating the supply of fresh and return air circulated, means for biasing the damper means to fresh air preventing position, electric motor means acting against said biasing means for positioning said damper means, means for supplying power to the electric motor means from the electric circuit of the fan means, a three wire control circuit for said electric motor means, said three wire control circuit including a common wire, a first control wire which is adapted in cooperation with said common wire to cause said electric motor means to operate in one direction, and a second control wire which is adapted in cooperation with said common wire to cause said motor means to operate in the opposite direction, condition responsive electric current controlling means for controlling said motor means, said ourrent controlling means comprising a potentiometer having a. slider member connected to said common wire, and a resistance connected across said control wires, a minimum position variable resistance interposed in one of said control wires between said potentiometer and said motor means for preventing said potentiometer from causing said motor means to move the damper means to a position stopping the supply of fresh air, and 

